Cut-off for sewing machines



Oct. 15, 1929. H. J. ISABELLE CUT-OFF, FOR SEWING MACHINES Filed Nov. 2, 1927 2 Sheets-Sheet I I W IVENTOR.

. HENRY J ZSABELLE;

BY ATTORNEi.

Oct. 15, 1929. J. ISABELLE 1,731,496

' GUT-OFF FOR SEWING mgcnmss 7 Filed Nov. 2. 1927 2 Sheets-Sheet 2 V J ma m fiE/ YJ ZSABELLE,

l' ATTORNEY.

Patented Get. 15, 1929 UNETED STATES HENRY J. ISABELLE, or FITGHBURG, MAssAcnUsn'rrs, ASSIGNOR, BY manor Ann PATENT I OFFEQE MESNE ASSIGNMENTS, TO WORCESTER KNLTTING 00., OF WORCESTER, MASSACHU- SETTS, A CORPORATION OF MASSACHUSETTS CUT-OFF FOR, SEWING MACHINES Application filed November 2, 192?. Serial No. 230,626.

The invention has for an object to perfect improvements in cut-offs adapted for use upon machines employed in making up tapework, such as belt-straps and other stitched straps, tape or other lengths requiring to be cut off at intervals, and in which it is desirable that such cutting off operation be entirely automatic, in order to insure uniformity. It is an object of the invention to provide a novel feed, timing and operating means for such a cut-oif device, and it is also an important aim of the invention to present a novel cutter construction. It is an important aim of the invention to presentv such a machine which is adapted to variations of adjustment to regulate the length of pieces cut. Another important aim of the invention is to provide a cutter of novelaction adapted to respond quickly when its function is desired and to quickly clear the path of the work, so as to avoid amming of the same between the presser foot and cutter, as well as obviating liability of obstructing movement of the work so as to impede action of the sewing mechanism or damaging of the work.

It is an important aim of the invention to present a construction of this character which is adapted to be incorporated upon sewing machines of familiar construction without requiring alterations in the structural features of such machines as heretobefore constructed, but being adapted-to mountingupon the bed plate on which the arm of such machine is carried.

Additional objects, advantages and features of invention reside in the construction, arrangement and combination of parts, as" will be more readily understood from the following description ,and the accompanying drawings, wherein V Figure 1 is an elevation from the left of the head of a sewing machine, equipped with my invention,

Figure 2 is an elevational view of my mechanism from the front, with the ordinary sewing machine parts omitted. I

Figure 3 is a similar view of the device from the righthand side of Figure 1, showingthe main or shuttle shaft,the other regular parts of the sewing machine being omitted for con venience in illustration.

The sewing machine illustrated may comprise a stitching mechanism including a work feed, which may be of any usual construction suitable for the work involved, the details of all of which as here involved,comprising no novel part of my invention,-are not illustrated.

There is illustrated the bed plate 10, which may be the regular bed-plate of the sewing machine upon which the cutter is installed.

Beneath there is shown the main shaft 11 ordinarily extending horizontally beneath the regular bed plate of a sewing machine. Rearwardly of this shaft a suitable distance a bracket 12 is provided, upon which there is mounted a rocker arm 18 which extends upwardly above the plate 10a short distance, its pivot being below the level of the shaft 11. A lateral arm 14. projects forwardly from this rocker arm, the arm 14 being fixed rigidly on the arm 13' and stopping short of the shaft 11 a short distance. Upon the shaft there is mounted an eccentric 15, connected by a link 16 to the adjacent end of the arm 14. Thus, upon operation of the shaft 11 the arm 13 will be oscillated.

Upon the upper side of the plate 10 two bearing brackets 17 are mounted, carrying revolubly a shaft 18. tween these brackets a ratchet wheel 19 is fixed. Pivoted upon the upper end of the arm 13 there is a pawl 20 engaging the ratchet, this pawl being held against the ratchet by means of a contractile spring 21' anchored upon a cross-bar 22 inserted through the brackets 17 beneath the shaft 18. The dog 23 is pivotally mounted at the opposite side of the ratchet to prevent reverse rotation of the ratchet, this dog being held in engagement with the ratchet by a contractile spring 24- also anchored to the bar 22. The bracket 17 and ratchet will ordinarily be located a distance to the right of the needle bar and presser foot mechanism, the left end of the shaft 18 projecting from the bearing and stopping short of a line from the presser foot at right angles to the axis of the shaft. At this left extremity a cam Upon the shaft be-.

25 is fixed upon the shaft, the cam having a spiral face with a deep notch 26 at the beginning or point of minimum radius, which notch may extend across the axis of the shaft, if desired, as shown, the cam face however, beginning higher than the depth of this notch and extending to a point of maximum height, from which there is a sheer part 27 in the cam, for a purpose to be described. Further to the left upon the plate 10 and spaced from the cam a goodly distance to provide a suitable path for the work passing rearward from the presser foot of the sewing machine, there is mounted a fixed vertical standard 28 upon which there is slidably adjustable a spring seat and guide block 29, having a lateral arm 30 toward the right through which there is slidable a vertical bar 31. The lower end of this bar is screwed into a horizontal arm 32 of a cutter frame having a vertical side bar 33 extending integrally therefrom immediately to the right of the extension 30, and having secured toits upper end a socket piece 34 into which there is set the upper end of the bar 31. The bar 33 of the cutter-frame lies closely adjacent the cam 25, and is provided with a wiper 35 arranged to be engaged by the cam, projecting across the cam for the purpose. The lower arm 32 of the cutter frame is extended and apertured to receive the standard 28 slidably therethrough, so that the standard serves in conjunction with the block 29 as a guide for the cutter frame. In addition, to minimize liability of displacement of the cutter frame from its path of reciprocation by the bearing of the cam against the wiper, an arm 36 is fixed in the lower arm 32 of the cutter frame and extended therefrom a distance rearwardly, then.

.tween the lower arm 32 of the cutter frame and the guide arm 30 a helical spring 37' is interposed, disposed loosely around the bar 31, while above the guide arm 30 a similar spring of shorter length and preferably of less strength is disposed loosely around the bar 31 engaging the block 34: for support of the cutter frame in initial position. The standard 28 projects above the guide 29, and is threaded and provided with nuts 39 the lower of which is adjusted snugly against the upper side of the guide 29, while the upper one serves as a lock nut. The wiper 3.5-for the shape of the cam shown and particular construction embodiedpreferably moves in a path alined with the axis of the shaft 18, and when the notch 26 is directly below the wiper, the springs 37 and 38 have pref erably very slight, if any, tension of compression, the upper spring simply supporting the cutter frame, and the wiper clearing the bottom of the notch a good distance, and being out of contact with the cam entirely. With the springs properly proportioned, adjustment of the device to get the relative positioning of the wiper with respect to the cam and work may be secured by adjustment of the guide 29 upon the standard 28, setscrews being shown engaged through the guide 29 bearing upon the standard to hold the guide in place. A blade 40 is secured removably to the front side of the lower arm 32 of the cutter frame, the plate 10 being suitably slotted thereunder to coact with the blade in severing a tape passing beneath the blade, and a sheer plate may be provided to coact with the blade, if desired, or other expedient employed, in accordance with practices in shearing devices.

lVith the wiper 35 adjusted in clearing re lation to the notch and cam, it is desirable that the blade 40 be located sufficiently above the path of the work fed from the sewing machine to clear the same and obviate liability of obstruction to the feed of the work from the stitching mechanism.

In the operation ofthis device, the sewing machine being operated and a tape fed thereto, the cam 25 will be rotated slowly'through the agency of the paw 1 20 from the shaft 11. The cam being initially positioned. with the notch 26 below the wiper, the cutter will. be initially supported in the position shown in Figure 2 by the spring 38, the spring 37 either being free of compression or very slightly compressed. As the face of'the' cam engages the wiper the cutter frame will be raised, compressing the spring 37 against the lower side of the arm 30. The spring 38 will be relieved entirely from compression and the block 34 will be raised above the spring 38 a distance. It should be appreciated that the lower arm 32, the bar 31, the bar 33'and the block34 as well as the arm 36, comprising the cutter frame are of asubstantial weight in connection with the operation now to be de scribed.

When the part of major radius of the cam passes the wiper center, and slightly before the wiper clears the cam, the pressure of the spring 37 transmitted through the wiper to the cam will cause a final movement of the cam I independently of the pawl 20, so that an immediate drop of the cutter frame will occur at the sheerpart 27 of the cam, and considerable momentum will be imparted to the blade 40 and its frame; The spring '38again engages the block 34 at the upper end of the cutter frame before the blade has engaged the tape, but the spring 38 will be compressed, and the blade will continue its movement through the work by momentum of'the parts. The spring 38 will quickly overcome" this momentum and return the blade to-initial position, as shown in Figure 2. For thispurpose,

the spring 38 must be comparatively stiff, as will be understood, so as to minimize oscillation of the cutter frame when stopped as described before it becomes inert, or before the wiper is again engaged by the face of the cam. The length of the parts cut by this device may be regulated to a considerable extent by use of the customary means provided on sewing machines for regulating the lengthof the stitch. It may also be varied by substituting ratchet wheels with more or fewer teeth.

It will be seen that a cut-off is presented involving few parts,and those of simple and sturdy structure, not easily deranged, the whole being of a character to give long serv ice and to function efliciently. No extreme nicety of adjustment is required to insure proper functioning of the device and its production and maintenance are correspondingly simplified and cheapend.

I claim:

1. A out off device for sewing machines comprising a vertically reciprocable blade having an initial work clearing position, a major spring associated therewith tending to resist its upward movement, a minor spring associated therewith in a supporting relation to support the blade yieldingly in initial position, a wiper fixed with respect to the blade, a cam in operative relation to the wiper having a recessed part to clear the wiper when in initial position sufficiently to permit cutting movement of the blade without obstruction by the cam, and having a face extending from the recess to lift the wiper against the action of the first mentioned spring when the cam is operated and having a sheer part from its apex to the recess, and means to operate the cam.

2. The structure of claim 1 in which a fixed standard is included parallel to the path of the blade, a seat member adjustably secured thereto, said springs being seated against the seat portion.

3. The structure of claim 1 in which a fixed standard is included parallel to the path of the blade, an adjustable seat member thereon, the mounting of the blade including a bar reciprocable in said seat and having cross portions at its ends, the said springs being helical springs around the bar at respective sides of the seat member and engaging at their outer ends the cross members.

4;. The structure of claim 1 in which a fixed standard is included parallel to the path of the blade, an adj ust-able seat member thereon, the mounting of the blade including a bar reciprocable in said seat and having cross portions at its ends, the said springs being helical springs around the bar at respective sides of the seat member and engaging at their outer ends the cross members, one of said cross members being extended to slidably engage around said standard.

5. The structure of claim 1 in which the cam is revoluble, a ratchet fixed coaxially therewith, a sewing machine shaft, a pawl operative upon the ratchet and operative connection between the sewing machine shaft and pawl.

.6. A sewing machine including a stitching mechanism, a vertical standard rearwardly of the stitching mechanism and to one side of the path of the work, a seat and guide thereon, a cutter frame including a vertical bar slidable in the seat and guide, a side bar parallel to thefirst bar and cross pieces carried thereby having the first bar set therein, the lower cross piece being extended and apertured to receive the standard slidably therethrough, a blade carried at the lower part of the frame, springs confined between the seat and guide and respective cross pieces to support the blade above the path of the work, means to coact with the blade to shear the work by downward movement of the blade across the path of the work, a cam movable beside the second named bar, a wiper on the bar, the cam having a recessed part clearing the wiper to permit cutting movement t ereof, a lifting face to engage the wiper to lift the cutter frame against the action of the lower spring, and having a sheer part next the recess to permit the frame to drop by reflexion of the spring, said recessed parts extending beyond the initial position of the wiper in the direction of cutting movement to permitmovement of the cutter frame by inertia past initial position for cutting operation, and means to operate the cam.

7 The structure of claim 6 in which an arm is extended from the cutter frame rearwardly thence laterallyfrom the path of the work opposite the standard, thence vertically downward, and a guide means engaged with the lower part thereof.

In testimony whereof I affix my signature.

HENRY J. ISABELLE. 

